Differential Strain-Dependent Ovarian and Metabolic Responses in a Mouse Model of PCOS

Several mouse models have been developed to study polycystic ovarian syndrome (PCOS), a leading cause of infertility in women. Treatment of mice with dihydrotestosterone (DHT) for 90-days causes ovarian and metabolic phenotypes similar to women with PCOS. We used this 90-day DHT treatment paradigm to investigate the variable incidence and heterogeneity in two inbred mouse strains, NOD/ShiLtJ and 129S1/SvlmJ. NOD mice naturally develop type 1 diabetes, and recent meta-analysis found increased androgen excess and PCOS in women with type 1 diabetes. 129S1 mice are commonly used in genetic manipulations. Both NOD and 129S1 DHT treated mice had early vaginal opening, increased anogenital distance and altered estrus cycles compared to control animals. Additionally, both NOD and 129S1 mice had reduced numbers of corpora lutea after DHT exposure, while NOD mice had decreased numbers of preantral follicles and 129S1 mice had reduced numbers of small antral follicles. NOD mice had increased body weight, decreased white adipocyte size, and improved glucose sensitivity in response to DHT, while 129S1 mice had increased body weight and white adipocyte size. NOD mice had increased expression of Adiponectin, Cidea, Srebp1a and Srebp1b and 129S1 mice had decreased Pparg in the white adipose tissues, while both NOD and 129S1 mice had increased expression of Glut4 and Prdm16 suggesting DHT may differentially affect glucose transport, thermogenesis, and lipid storage in white adipose tissue. DHT causes different ovarian and metabolic responses in NOD and 129S1 mice suggesting that strain differences may allow further elucidation of genetic contributions to PCOS

Use of home cage wheel running to assess the behavioural effects of administering a mu/delta opioid receptor heterodimer antagonist for spontaneous morphine withdrawal in the rat

Opioid abuse is a major health problem. The objective of the present study was to evaluate the potentially disruptive side effects and therapeutic potential of a novel antagonist (D24M) of the mu-/delta-opioid receptor (MOR/DOR) heterodimer in male rats. Administration of high doses of D24M (1 & 10 nmol) into the lateral ventricle did not disrupt home cage wheel running. Repeated twice daily administration of increasing doses of morphine (5-20 mg/kg) over 5 days depressed wheel running and induced antinociceptive tolerance measured with the hot plate test. Administration of D24M had no effect on morphine tolerance, but tended to prolong morphine antinociception in non-tolerant rats. Spontaneous morphine withdrawal was evident as a decrease in body weight, a reduction in wheel running and an increase in sleep during the normally active dark phase of the circadian cycle, and an increase in wheel running and wakefulness in the normally inactive light phase. Administration of D24M during the dark phase on the third day of withdrawal had no effect on wheel running. These data provide additional evidence for the clinical relevance of home cage wheel running as a method to assess spontaneous opioid withdrawal in rats. These data also demonstrate that blocking the MOR/DOR heterodimer does not produce disruptive side effects or block the antinociceptive effects of morphine. Although administration of D24M had no effect on morphine withdrawal, additional studies are needed to evaluate withdrawal to continuous morphine administration and other opioids in rats with persistent pain.18 month embargo; published online 6 October 2020This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Rodent models of mental illness in polycystic ovary syndrome: the potential role of hypothalamic–pituitary–adrenal dysregulation and lessons for behavioral researchers

Polycystic ovary syndrome (PCOS) is the most commonly diagnosed endocrine disorder in women of reproductive age, with phenotypes including ovarian and metabolic dysfunctions. Women with PCOS also show increased rates of mental illness, dysregulation of the hypothalamic–pituitary–adrenal (HPA) axis, and altered responsiveness to stressors that may contribute to the higher rates of mental illness, specifically depression and anxiety. Animal models of PCOS have provided insight into the ovarian and metabolic mechanisms that underlie the syndrome, and several models have been used to study the behavioral consequences associated with PCOS in the laboratory. Several studies in rodent models of PCOS demonstrate changes in anxiety-like behavior, but researchers often neglect to report procedural details or behavioral data crucial to interpreting the differences observed in those studies. Additionally, the impact of potential HPA dysregulation in animal models of PCOS may influence behavioral findings, although only three studies to date have examined this. As such, researchers should consider and report stress-associated variables (e.g., time of day, light/dark cycle, light intensity, housing, and procedures to control experimenter and litter effects) that may influence depression- and anxiety-like behaviors in rodents. This review will summarize the behavioral and HPA-related studies in women with PCOS and rodent models of the disease, and provide considerations for future studies